Aerostatic Rotor Disc Support for Axial Flutter Control
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Solution Overview
Problem
Large-diameter rotor devices in engines and driven machines often experience flutter due to alternating axial motion, which increases with radius, leading to undesirable inertia and torque limitations, particularly in axial flux motors and gas turbines, where traditional ball bearings fail to provide precise support and are heavy or limited in precision.
Innovation Solution
The implementation of an aerostatic bearing system with a stator-side and rotor-side bearing surface and a bearing gap between them, supporting the rotor device's outer circumference, allowing for precise concentricity and preventing axial flutter by using micro-holes for gas outlet nozzles that form a high-load capacity air bearing, enabling support of axial forces without increasing mass or diameter limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the rotor device is made stiffer to avoid fluttering, then the rotational stability is improved, but the mass of the rotor device increases significantly
Solution Approach 1:
The patent replaces traditional mechanical ball bearings with an aerostatic bearing system that uses a controlled air cushion to support the rotor device. This substitution eliminates the need for mechanical contact and the associated friction, while providing precise axial positioning without requiring increased rotor stiffness or mass.
Solution Approach 2:
The patent introduces a bearing gap between the rotor device and stator device, which is filled with air to create an aerostatic bearing. This pneumatic system provides axial support forces that stabilize the rotor device during operation, preventing fluttering without increasing the rotor's mass or stiffness requirements.
2Power
If the permanent magnets are placed further radially outward to increase torque, then the torque generation is improved, but the bending forces on the rotor disk increase causing flutter
Solution Approach 1:
The aerostatic bearing system provides axial support forces that counteract the bending forces generated by radially outward permanent magnets. The bearing gap and air cushion enable the rotor disk to maintain stability even with high-torque configurations that would otherwise cause excessive bending and flutter.
Solution Approach 2:
The aerostatic bearing generates upward axial support forces that counterbalance the downward bending forces acting on the rotor disk from radially spaced permanent magnets. This counteracting force system allows the rotor to maintain stability while generating high torque.
3Reliability
If traditional ball bearings are used to support the rotor device, then the axial support is provided, but the precision and load capacity are limited
Solution Approach 1:
The patent replaces mechanical ball bearings with an aerostatic bearing system that uses air pressure to provide axial support. This substitution achieves superior precision and load capacity by eliminating mechanical contact, reducing friction, and providing a compliant support system that maintains precise concentricity under varying loads.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution ensures precise concentricity and prevents axial flutter, allowing for larger support radii with lower mass and higher torque generation, while avoiding the diameter limitations of traditional rolling bearings, enabling the construction of compact and powerful engines with large diameters.
Implementation Method 1
an aerostatic bearing including a stator-side bearing surface formed on the at least one stator device and a rotor-side bearing surface formed on the at least one rotor device and a bearing gap formed between the stator side bearing surface and the rotor side bearing surface
Implementation Method 2
using micro-holes for gas outlet nozzles that form a high-load capacity air bearing, enabling support of axial forces without increasing mass or diameter limitations
Data Source
AI summary
An electric motor or driven machine including a structure; a stator device fixed at the structure; a rotor device including an outer circumference; and a rotor shaft coupled or couplable to the rotor device for torque transmission and supported rotatable about an axis of rotation and substantially axially fixed in or on the structure, wherein the rotor device is axially supported proximal to its outer circumference in an axis-parallel direction by an aerostatic bearing including a stator-side bearing surface formed on the stator device and a rotor-side bearing surface formed on the rotor device and a bearing gap formed between the stator side bearing surface and the rotor side bearing surface, wherein the rotor device is formed by a rotor disc, wherein circumferentially spaced and radially extending permanent magnets of an electromagnetic operating device are provided at the rotor disk, radially inside from the aerostatic bearing.